[PDF] - Basic Dermatology Procedures Basic Dermatology Procedures Liquid PDF Document

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Basic Dermatology Procedures for the Non‐dermatologist

Lindy P. Fox, MD

Associate Professor Director, Hospital Consultation Service Department of Dermatology University of California, San Francisco

lindy.fox@ucsf.edu

I have no conflicts of interest to disclose

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Basic Dermatology Procedures

Liquid Nitrogen
Skin Biopsies
Electrocautery

Liquid Nitrogen Cryosurgery

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Liquid Nitrogen Cryosurgery

Indications

– Benign, premalignant, in situ malignant lesions

Objective

– Selective tissue necrosis

Reactions predictable

– Crust, bulla, exudate, edema, sloughing

Post procedure hypopigmentation

– Melanocytes are more sensitive to freezing than keratinocytes

Liquid Nitrogen Cryosurgery Principles

‐ 196°C (−320.8°F)
Temperatures of −25°C to −50°C (−13°F to −58°F)

within 30 seconds with spray or probe

Benign lesions: −20°C to −30°C (−4°F to −22°F)
Malignant lesions: −40°C to −50°C.
Rapid cooling  intracellular ice crystals
Slow thawing  tissue damage
Duration of THAW (not freeze) time is most

important factor in determining success

Am Fam Physician. 2004 May 15;69(10):2365‐2372 From: Bolognia, Jorizzo, and Schaffer. Dermatology 3rd ed. Elsevier 2012

Liquid Nitrogen Cryosurgery

Fast freeze, slow thaw cycles

– Times vary per condition (longer for deeper lesion) – One cycle for benign, premalignant – Two cycles for warts, malignant (not commonly done)

Lateral spread of freeze (indicates depth of freeze)

– Benign lesions 1‐2mm beyond margins – Actinic keratoses‐ 2‐3mm beyond margins – Malignant‐ 3‐5+mm beyond margins (not commonly done)

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Liquid Nitrogen Cryosurgery Technique

Hold spray gun 1‐1.5cm away from target
Freeze until ice field fills the margin
Maintain the spray for the appropriate time

BEYOND initial time of ice field formation

If more than one cycle required, allow for

complete thawing before beginning next cycle

Cryosurgery for Common Warts

Freeze time 20‐60 seconds
Margin‐ 2‐3mm
Thaw 30‐45 seconds
TWO cycles better than one
Repeat every 3‐4 weeks
Average # of warts cleared= 40%
Average # of treatments to clear

warts = 12

– ONE YEAR!

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Cryosurgery for Planar Warts

May consider

cotton tipped applicator technique

Cryosurgery for Actinic Keratoses

One freeze‐thaw cycle
margin‐ 2‐3mm
Freeze time

– AK 5‐7s – Actinic cheilitis 10‐20s

www.dermquest.com

Cryosurgery for Seborrheic Keratoses

Freeze‐ thaw cycle

depends on thickness

Thin/flat‐ freeze 5‐10s
Large/thick‐freeze >10s,

may need second cycle

Cryosurgery for Lentigines

Quick 3‐4s freeze
Avoid overfreezing

– Risk of hypopigmentation

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Cryosurgery for SCC in situ*

One 30 second freeze

Or

Two 20 second freezes
Close follow up

*ED+C still preferred treatment option

Skin Biopsies Skin Biopsy

Procedure itself is easy
Knowing when and where to biopsy much

more difficult

Pathologist can only comment on the tissue

provided (not what’s left on patient)

Potential pitfalls in technique

Skin Biopsy Types

Curettage
Snip/scissors
Shave biopsy
Saucerization
Punch
Incisional
Excisional (in toto)

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Curettage with Biopsy

Samples epidermis only
Clinically benign lesions involving the epidermis

– Verrucae (warts), seborrheic keratoses, actinic keratoses

Send pathology at same time as treating the

lesion

Limitations

– Limited to the epidermis – Fragmented tissue

From: Bolognia, Jorizzo, and Schaffer. Dermatology 3rd ed. Elsevier 2012

Hold like pencil
Draw pressure under the lesion (epidermis)

Snip/Scissors Biopsy

Pedunculated lesions
Benign growths

– Acrochordons (skin tags) – Filiform warts – Pedunculated nevi

From: Bolognia, Jorizzo, and Schaffer. Dermatology 3rd ed. Elsevier 2012

If very thin attachment to skin (stalk) don’t need anesthesia
Use iris or Gradle scissors
May require hemostasis with aluminum chloride, electrodesiccation

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Shave Biopsy

Samples epidermis and papillary (superficial)

dermis

Ideal for elevated lesions involving the epidermis

and superficial dermis

– Inflammatory dermatoses of epidermis, superficial dermis (psoriasis, eczema, CTCL, lichen planus) – Nevi, benign adnexal tumors – Diagnosis of basal cell or squamous cell carcinoma – Diagnosis of lentigo maligna (MIS)

Am Fam Physician. 2011 Nov 1;84(9):995‐1002 Onsurg.com www.hovesskinclinic.co.uk From: Bolognia, Jorizzo, and Schaffer. Dermatology 3rd ed. Elsevier 2012

Be sure to get below simple hyperkeratosis and upper dermis
Palms, soles, hyperkeratotic lesions
Require hemostasis with aluminum chloride, electrodesiccation

Good Shave Biopsy

Slide courtesy of Jeff North, MD

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Saucerization Biopsy

Deeper biopsy with intentional deeper placement of

the blade

Samples epidermis and superficial and deep dermis
Advantage

– Histologic examination of the entire circumference of the lesion with adequate depth to assess invasion

Ideal for

– Inflammatory dermatoses with dermal infiltrate – Atypical pigmented lesions (to r/o melanoma) – Keratoacanthoma/SCC

From: Bolognia, Jorizzo, and Schaffer. Dermatology 3rd ed. Elsevier 2012

Intention is to get to deep dermis
Requires hemostasis with aluminum chloride, electrodesiccation

Punch Biopsy

Samples epidermis, dermis and superficial subcutaneous fat
Varying barrel sizes‐ 2mm‐ 8mm
Ideal for

– Inflammatory dermatoses with deep dermal infiltrate (lupus) – Infiltrative diseases (amyloid, sarcoid, lymphoma cutis) – Blistering diseases (pemphigus, pemphigoid) – Depressed lesions (scleroderma)

Limitations

– Only samples portion of larger lesion – Requires suture (>3mm) – Not ideal for subcutaneous lesions

NO contraindications to punch biopsy other than avoiding

bowel and brain

Punch Biopsy

Stabilize skin around punch with free hand
Twist with firm downward pressure in one direction
Gently lift tissue with forceps at edge of epidermis (do not crush)
If plug not elevating, angle scissors downward to base
Try to make sure there is some fat at the base of the sample

Slide courtesy of Wilson Liao, MD

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Good Punch Biopsy

Slide courtesy of Jeff North, MD

Incisional Biopsy

Samples epidermis, dermis, subcutaneous fat
Removes wedge from center or edge of lesion
Ideal for

– Large tumors – Subtle diseases of connective tissue – Diseases of the fat (panniculitis) – Diseases of the fascia

From: Bolognia, Jorizzo, and Schaffer. Dermatology 3rd ed. Elsevier 2012

Excisional Biopsy

Samples epidermis, dermis, subcutaneous fat
Intended to be definitive treatment
Ideal for

– Suspected invasive melanoma

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Skin Biopsies‐ Potential Pitfalls

Crush artifact
Leaving part of tissue in punch tool
Multiple specimens, mislabeling

Crush Artifact

Slide courtesy of Jeff North, MD

Failure to Deliver

Leaving part of the biopsy in the punch tool

Biopsy

Slide courtesy of Jeff North, MD

Multiple Biopsy Specimens

Critically important to have an established

protocol/routine to ensure the correct biopsy goes in the correct bottle A B C

Slide courtesy of Jeff North, MD

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Shave Biopsy Tray

Video courtesy of Wilson Liao, MD

Punch Biopsy Tray

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How to biopsy a specific lesion

Lesion Type of biopsy

Papulosquamous (eczema, psoriasis) Shave or saucerization biopsy r/o melanoma Saucerization or excisional biopsy Blister Punch biopsy at the edge for H+E and DIF Wart, seborrheic keratosis, actinic keratosis Shave biopsy or curettage Scalp (alopecia) Punch biopsy from hair containing region adjacent to alopecia, request transverse sections

Where to Biopsy

Lesion Location of biopsy Tumor Thickest portion, avoid necrotic tissue Blister Edge of the lesion, include about 2mm

f blister edge; send for H+E and DIF

Ulceration/necrotic lesion Edge of ulcer or necrosis plus adjacent skin Generalized polymorphic eruption Characteristic lesion of recent onset (+/‐ more developed lesion) Small vessel vasculitis (palpable purpura) Characteristic lesion of recent onset (ideally <24 hours old)

Adapted from: Bolognia, Jorizzo, and Schaffer. Dermatology 3rd ed. Elsevier 2012

Direct Immunofluorescence

Location of the biopsy depends on differential

diagnosis

Michel’s medium (not formalin)
Vasculitis‐ lesional skin from an early lesion
Lupus

– DLE/SCLE Lesional skin – SLE‐ Lesional, uninvolved can be positive as well

Blistering

– Peri‐lesional

Slide courtesy of Jeff North, MD Slide courtesy of Jeff North, MD

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DIF‐ peri‐lesional

Eclipsing the edge of new

blister

Being too far from a blister

can cause false negative DIF

DIF in Pemphigoid and Pemphigus

Slide courtesy of Jeff North, MD Photo courtesy of Kari Connolly, MD

DIF in Other Immunobullous Disease

Dermatitis herpetiformis
Up to 1 cm away from lesion
Don’t overlap the clinical lesion
Higher risk for loss of epidermis and

destruction of Ig by the neutrophilic inflammatory infiltrate

Serology: anti‐transglutaminase and anti‐

endomysium antibodies also helpful

Slide courtesy of Jeff North, MD

Electrosurgery Electrosurgery

Electrodesiccation

– Superficial tissue destruction

Electrocoagulation

– Deep tissue destruction

Electrosection

– Cutting

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Electrosurgery

Electrodesiccation

– Superficial tissue destruction

Electrocoagulation

– Deep tissue destruction

Electrosection

– Cutting

Electrodesiccation

Damped, high‐

voltage current

Causes superficial

tissue damage via dehydration

Electrodesiccation and Electrofulguration

Am Fam Physician. 2002 Oct 1;66(7):1259‐1267

Electrodesiccation Electrofulguration

Electrodesiccation Indications‐ Epidermal Lesions

Acrochordons
Actinic keratosis
Angioma (small)
Hemostasis
Lentigo
Seborrheic keratoses/dermatosis papulosa

nigra

Verrucae

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Electrodesiccation for Epidermal Lesions‐ Technique

Typically doesn’t require anesthesia
Use lowest setting that produces a very subtle

gray char

May see pinpoint bleeding (indicates you have

reached dermis and time to stop)

Doesn’t require post procedure wound care other

than vaseline

Target lesions “fall off” within 1‐2 weeks
Typically doesn’t scar or lead to pigmentary

damage if done correctly

From: Bolognia, Jorizzo, and Schaffer. Dermatology 3rd ed. Elsevier 2012 From: Bolognia, Jorizzo, and Schaffer. Dermatology 3rd ed. Elsevier 2012 From: Bolognia, Jorizzo, and Schaffer. Dermatology 3rd ed. Elsevier 2012

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From: Bolognia, Jorizzo, and Schaffer. Dermatology 3rd ed. Elsevier 2012 From: Bolognia, Jorizzo, and Schaffer. Dermatology 3rd ed. Elsevier 2012

Basic Dermatology Procedures Summary Points‐ Liquid Nitrogen

Duration of thaw determines amount of tissue

damage

Warts require monthly treatments for 12 months
Avoid over freezing (to avoid hypopigmentation)

Basic Dermatology Procedures Summary Points‐ Skin Biopsies

Pathologists can only comment on the tissue

provided

Curettage is a good way to treat warts, SKs
Shave/saucerizaton biopsies are best for

inflammatory lesions, BCC, SCC

Punch biopsies are best to evaluate deep dermis
Incisional biopsies are the best way to assess the

subcutis

Try to perform excisional biopsies for melanoma,

but large saucerization acceptable

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Electrodesiccation is a good option to

cosmetically treat seborrheic keratoses, dermatosis papulosa nigra

If curette or shave remove a wart,